Question

a machine gun fires a bullet of mass 40 g with a velocity 1200ms.the man holding it,can exert a maximum force of 144N on the gun.how many bullets can he fire per second at the most?

Answer 1

Mass of each bullet = 40 g = .040 kg

Velocity of each bullet = 1200 m/s

Let 'n' be the number of bullets fired per second. Then, change in momentum of the bullets coming out per second is,

= force on the man

=> n (0.040)(1200) = 144

=> n = 3

Answer 2

F = nmv/t

n = Ft / (mv)
= (144 N × 1 s) / (40 × 10^-3 kg × 1200 m/s)
= 3

Man can fire 3 bullets per second